...an old toothbrush.一把旧牙刷The toothbrush gently removes plaque without damaging the gums.这种牙刷可以温和去除牙菌斑而不损伤齿龈。As soon as the bristles on your toothbrush begin to wear, throw it out.牙刷毛一开始磨损，就把它扔掉。He was short and tubby an...
There is a heterogeneous mass of papers in the teacher's office.老师的办公室里堆满了大批不同的论文。He believes that this equation connot be applied to heterogeneous flow.他认为该式不能应用到非均质流型.Many processes that are essential to the chemi...